DE10003374C1 - Process for making prototypes or molds from molding material - Google Patents

Abstract

The invention relates to a method for producing molds from molding material, the molding material being subjected to strengthening energy by means of a strengthening tool, the strengthening tool being moved three-dimensionally in or through the molding material, the shape, which is designed as a three-dimensional freeform, thereby being strengthened of the molding material is formed and the excess molding material is removed after solidifying and forming.

Description

The invention relates to a method for producing molds made of molding material. The production more defined three-dimensional or spherically curved body from one Molding material is required in many areas, such as. B. for the production of molds for metal, concrete, plaster, Wax, plastic, etc. but also for direct production of elements from the aforementioned materials. Furthermore it is necessary to have defined areas for the production of To be able to design terrain models.  

It is state of the art for the production of casting molds known to produce a model, which is then in a suitable Molding material is shown. The making of one Model is expensive and time consuming. Furthermore are large amounts of z. T. environmentally harmful molding material consumed.

For the production of z. B. Terrain models is still that Hand modeling is known, where the molding material is molded manually becomes. This procedure offers the greatest possible degree of freedom when designing surfaces. However, here is the manual effort very high and the shape accuracy low. The The geometry of the modeled shape is not defined re-modifiable. Ultimately, this results in multiple toxic molding material a health hazard for the modeling person.

The process is a form of rapid prototyping because of the form or the prototype without machining processes directly from the Geometry data is generated. The process is based on the Application of handling devices, e.g. B. Industrial robots for guiding tools that Solidify the molding material and thereby the desired shape form.  

For example, using rapid prototyping thermosetting molding material for the production of casting cores known as laser sintering. In this procedure successively thin layers thermally curable Molded material just applied and with a laser beam hardened. The beam travels along paths that the Describe the area of the molding material to be hardened. On Such a method has the disadvantage that the focal spot of the laser is small and therefore it is comparatively long takes until the surface of a layer to be hardened has been removed is. Furthermore, this procedure is necessary several times, since each Layer must be cured individually. So z. B. a Produce structures with a volume of approximately three liters a manufacturing time of five to ten hours is necessary. Finally, the uncured molding material must be one Removed layer after curing. Furthermore, the Laser sintering as well as with all other known so far Rapid prototyping processes working in layers, d. H. generative process very limited the construction volume (smaller than 250 l).

WO 90/03893 A1 describes the production of a three-dimensional body using rapid prototyping Process from successive layers by cutting, Merging, etc. by means of an energy beam, whereby the material surrounding the body is later removed. Also the production takes place in horizontal layers.  

Such a rapid prototyping process does offer a high level Process accuracy, in cases where such is not required, e.g. B. with very large prototypes of about 1 m × 1 m × 1 m or larger, that's a lot expensive procedures not economical.

A rapid prototyping process with industrial robots in the Meaning that no cutting processes take place (more subtractive Process), but material is added (additive or generative process) is described in DE 198 51 224 C1, which is a process for producing defined free-form surfaces in molding material made of pasty material or bulk material, which means an application device applied to an order reason has been disclosed by a rolling device. This The process is in contrast to the working in shifts previously described rapid prototyping process for large Suitable for prototypes or molds. It becomes the prototype by applying a layer of molding material to a preset shape and by three-dimensional modeling produced by a robot-guided rolling tool. The disadvantage here is that two robot tools are required are, namely to apply and to model the Molding material. Furthermore, to achieve a defined Density of the molding material layer of the molding material applied in doses become.

It is therefore an object of the invention to provide a method for Manufacture of prototypes or molds from molding material provide the disadvantages of the prior art avoids.

The invention solves this problem by providing a Process for producing molds from molding material with im Molding material "diving" and three-dimensionally guided Tools, the molding material using a Solidification tool applied with consolidation energy and the hardening tool three-dimensionally in or is moved through the molding material, whereby the shape, which is designed as a three-dimensional free form, by Solidifying the molding material is formed and which excess molding material after solidification and the Forming is removed. Such a method offers the Advantage, in a container filled with molding material the surface, d. H. local and within the molding material to solidify specifically and in this way a prototype or to produce a shape. In the inventive The process immerses the hardening tool in the process Molding material and moves similar to one Liquid through the unsolidified molding material. The Mold production can be done in layers, with the Layers don't have to be horizontal, but it can also a completely free three-dimensional form in one Operation.  

The removal of the unsolidified molding material after the Forming can be done by vacuuming or depending on the size of the mold Empty out.

Under molding material, both quartz sand-based Molded materials, but also not quartz sand-based materials be understood.

Compared to the conventional, layered Rapid The inventive method offers prototyping the advantage of working at a higher process speed to be able to and at the same time a practically unlimited To provide construction volume. Especially for This offers prototypes with large permissible tolerances inventive method an economical alternative.

Compared to the method known from DE 198 51 224 C1 the method according to the invention offers the advantage that no additional robot tool for applying the molding material is required, moreover, the elaborate Metering device saved and it can save quartz sand-based molding materials also other molding materials, e.g. B. Liquids are used.

In particular, it can be provided that the consolidation by means of mechanical, thermal, chemical or Light energy takes place. That comes as mechanical solidification  Compaction for example by a "rammer" in question, the tool making oscillating movements. The Form then forms through the densified areas. Furthermore, it can be provided that alternatively or additionally the solidification of the molding material is thermally based, so that z. B. by gassing with hot gas or introducing one hot liquid hardens the molding material. A hardening can also with the help of light energy, e.g. B. UV light or Laser light can be brought about.

To entry z. B. a reactive or hot gas can Hardening tool z. B. with a closable nozzle be equipped. The entry of thermal energy can alternatively also using a tool with heating and / or coolable face.

Another alternative of feeding Solidification energy can be the addition of chemical energy through a chemical reaction. So z. B. a through chemical reaction hardening quartz sand based Molding material with reactive gas or liquid, e.g. B. Carbon dioxide similar to the water glass process at Manufacture of molds and cores for foundry technology, fumigated become.

In addition to thermosetting, the molding materials come quartz sand-based molding materials also clay-bound  quartz sand-based molding materials for mechanical Compression and other pasty and bulk goods Molded materials for use, which are characterized by one of the let the above-mentioned process solidify. Furthermore can also appropriate liquids or gels are used.

Further features of the invention result from the others Registration documents.

In the following, the invention will be described with reference to the drawing are explained.

Show:

Fig. 1 is a schematic representation of the rapid prototyping method according to the invention;

Figure 2 is a tool for solidifying by means of fumigation.

Fig. 3 types of motion of a compression tool;

Fig. 4 oscillatory movements of the tool and

Fig. 5 shows a nozzle for gassing the molding material.

Fig. 1 shows a schematic representation of the rapid prototyping method according to the invention for the production of molds from molding material. Here, molding material 10 is filled into a container 12 for receiving the molding material 10 until the container 12 is substantially filled up to its upper edge. Subsequently, a tool 14 , which is guided through a handling device or through an industrial robot 16 , is immersed in the molding material 10 . In this respect, the tool 14 is a "diving tool". The immersed tool 14 acts on the molding material 10 with solidification energy, here for example in the form of hot gas ( FIG. 2).

The molding material 10 is a thermosetting quartz-based molding material that hardens with the addition of thermal energy. The diving tool 14 is guided by the robot 16 in the molding material 10 , whereby it moves partly as if through a liquid and partly solidifies the material 10 . The shape or prototype 20 is essentially created in one work step. After completion of the prototype 20 , it is removed from the container 12 and the excess molding material 22 , which has not been cured by the thermal energy, can be added to the production process again. The excess molding material 22 is removed by suction, after which the prototype 20 is removed from the container 12 .

FIG. 2 shows a diving tool 14 (identical parts are provided with the same reference numbers), which is guided through a handling device or an industrial robot 16 . Gas is introduced into the tool 14 from a gas bottle 24 via a gas supply 26 via a pump 28 . The tool 14 moves with its head 30 in a container 12 which is filled with molding material 10 up to its upper edge. The head 30 of the tool 14 is guided so that the tool tip 32 , which contains a nozzle for the exit of the gas, is directed towards the molding material to be solidified. The molding material to be solidified is indicated here by a double-dotted line. The molding material 10 is solidified here in sections, the tool 14 not necessarily having to be moved along horizontal layers. The already solidified molding material 34 is shown with dark hatching.

If the tool 14 is to be moved with its tip 32 within the loose molding material 10 , the nozzle for closing the hot gas is closed, so that no further solidification occurs.

Fig. 3 shows an immersion tool which enters in a mechanical way the compression energy for solidification of the molding material 10 in the same. The molding material in this case is clay-based molding material based on quartz sand. The molding material 10 is in turn located within a container 12 . The tool 14 can be advanced in the vertical direction (thick arrow), whereby it can simultaneously perform an oscillatory movement, which is represented by the small arrows or the double arrow.

For compacting, the hardening tool 14 performs an oscillating or vibrating up and down movement, which is shown in the first image (a) of the associated FIG. 3. A force sensor detects when the desired hardening is reached. By lifting the hardening tool, as shown in image (b) of FIG. 3, loose molding material can be fed under the tool 14 according to the curved arrows. The loosening of already solidified molding material (picture (c) of Fig. 3) or the removal thereof can be done by oscillating sideways movement or circular movement.

Picture (d) shows a movement leading to penetration in loose Molded material is used. This is an oscillating Pendulum movement together with a feed movement carried out.  

With a translatory sideways movement with a superimposed oscillation, a translatory tool movement can be realized through loose molding material 10 . The tool thus moves through the molding material 10 as if through a liquid in which the particles move around the tool 14 .

Fig. 4 shows again the possible movement of a submerged compaction tool with oscillatory movements. The oscillatory movement is represented by the double arrow, whereas the feed movement is represented by the simple thick arrow. The oscillating movements can take place in the direction of the tool feed (b), but also orthogonally (a). Furthermore, rotational movements can be carried out normally (c) and in the feed direction (d), that is to say axially or radially. Finally, a pendulum movement (e) of the compacting tool is possible. Movements that result from combinations of these basic movements are also possible. It is also conceivable to apply ultrasound to the tool.

Fig. 5 shows, finally, a nozzle for feeding the solidifying agent, such as a hot or a reactive gas or a liquid that reacts with the molding material. The arrows 40 show the directions of movement of the nozzle core 42 , which can be moved into an opening 44 of the nozzle housing 46 , and seals it in a sealed manner. If the nozzle core 42 is not fully retracted into the opening 44 , ie if it does not close the opening 44 , hot or reactive gas or liquid 48 flows along the nozzle core 42 through the opening 44 and comes into contact with the molding material.

Claims (8)

1. A process for the production of molds from molding material, wherein the molding material is subjected to a hardening energy by means of a hardening tool, characterized in that the hardening tool immersed in the molding material is moved three-dimensionally in or through the molding material, thereby shaping the mold as a three-dimensional freeform is formed, is formed by solidifying the molding material, and the excess molding material is removed after the solidifying and the molding. 2. The method according to claim 1, characterized in that that the consolidation by means of mechanical, thermal and / or light energy takes place. 3. The method according to claim 1 or 2, characterized characterized in that the solidification by means of a chemical reaction takes place. 4. The method according to claim 2 or 3, characterized characterized in that the solidification of the Molding material by gassing with a hot or  reactive gas or by introducing a hot or reactive liquid. 5. The method according to any one of the preceding claims, characterized in that as a molding material quartz sand-based molding material or a bulk material Quartz sand base, a pasty material, a Liquid or gel is used. 6. The method according to any one of the preceding claims, characterized in that forming the shape by means of an oscillating movement performing consolidation tool. 7. The method according to any one of the preceding claims, characterized in that the Solidification tool a nozzle for the escape of gas and / or liquid. 8. The method according to any one of the preceding claims, characterized in that the Solidification tool a hot and / or coolable End face for the introduction of thermal Has strengthening energy.